Apparatus for molding sliders for slide fasteners



Aug. 15, 1950 Filed July 14, 1945 J. BOLTEN, JR 2,519,171

APPARATUS FOR MOLDING SLIDERS FOR SLIDE FASTENERS 2 Sheets-Sheet 1 \yfi 27 I I/ Z I -L |/l\\ :5

Fla 3 INVENTOR. John Bo/Ten Jr. BY

Aug. '15, 1950 J. BOLTEN, JR

APPARATUS FOR MOLDING SLIDERS FOR SLIDE FASTENERS Filed July 14, 1945 2 Sheets-Sheet 2 Patented Aug. 15 1950 UNITED STATES PATENT OFFICE APPARATUS FOR MOLDING SLIDERS FOR SLIDE FASTENERS John Bolten, Jr., Andover, Mass., assignor-to T-he Bolta Company Lawrence, Mass, a corporation of Massachusetts ApplicationJuly-M, 1945, Serial"Nor605,044i

4.Claims. (01.18-42) This invention relates toimprovements in mouldsfor manufacturing sliders for slidingv snap fasteners; in which tapes having complementary interlocking members pass through spacedopenings or mouths in the slider into a relatively narrow passage where they are, automatically interlocked as the slider is moved ina direction to. causev the interlocking elements to enter the slider and upon reverse movement of the. slider topermitseparation of the tapes and the. interlocking members thereon. Usual moulds for makingfsliders. of this character compriseastationary; and a. relatively movable mould section having complementary cavities for the side walls of the slider which. are parallel to the contacting. surfaces. of the mould, and inorder to form. the passages through the slider it is necessary that the cores, which form the. inside. of the slider, shall be movable so. that the finished product canbe removed from the mould... Such cores. are usually slid. back, and forth by mechanical means and there is no possibility of anchoring the free ends. of. the respective cores. in an opposite half of the mould. Such. cores. are commonly known as floating cores. In die casting or injection moulding the floating core. is an undesirable construction. and is very. like to lead to breakage or displacement of the end of the core, as the cores are not firmly anchored when the. molten material. is injected. or cast into the.

mould members are; separated: and thereupon to 1 detach: the slider from the mould members.

These and other objects andfeatures of the invention will more fully appear from the following descriptionand the: accompanying drawings and will be particularly pointed outinthe claims. 1

A preferred embodiment of the invention is illustrated in. the. accompanying drawings, in which: I

Fig. 1 is a side. elevation of a conventional typeofslider;

Fig. 2 is a. vertical sectional view' on line 2-2 Fig.1;

Fig. 3 is-an enlargedverticalv sectional view of. the complementary mould halves in closed position with the. cavities of, the respective mould halves, which. conform. to the body of theslide; having their greatest areas registering at the. contacting surfaces of the mould and extending inwardly therefrom, into. the respective mould sections;

Fig. 4 is a vertical sectional view on line. 4-4 Fig. 3;

Fig. 5 is a. detail view, partially broken away;

showing the mould halvesin closed position. with mould. Thisis especially important. in injection.

moulding where. injection and clamping pressures are from 20,000. pounds per square inch, or more.

One. of'the principal. objects of the present invention is. to provide a moulding construction in which, complementary cores for the passages;

through-the slider are sointerengaged as to avoidthe floating condition and insure accuracy and longevity-of use.

Afurther object of. the invention is to provide a constructionin which the respective. cores may be. detachably secured inthe mould sectionsand readily replaced if necessary if the core becomes broken, chipped, or otherwise injured.

A further object, of the invention is to anchor such replaceable cores so; securely in. the. respective, mould halves thatfor all practicalpurposes they become. a. part of the. mould. and all possibility, of. play eliminated.

A further object of. the. inventionis to provide a. mould construction having a. sliding core for forming the Pull. slot. of the, usual bridge with meansfor actuatingv the core, upon relative move.- ment of the mould. members toinsertthel core the core for forming the: pull slotof the slide crossing the bridge channel of the mould; and,

Fig. 6- is:a view similar to Fig. 5: illustrating; the mould members. in: separated, position and. theslider withdrawn.

A conventional form of slider which is illustrated in Figs. 1. and 2 comprises'a. slider body having parallel front and rear side members 1: and 2 which: are connectedtogether by a central Web 3 to provide entrances 4; and 5 for the respective stringers and. the complementary series.- of interlockin membersthereon. The entrances: l and 5 lead to a common guideway 6 having; suitably spaced edge Walls 1 and 8' to permit the passage of the. stringer therethrough. A bridge 9; which is integrally secured at its. ends. to the side wall,8,,provides a pull: slot [O in which the usual puller H is slidably mounted. The

greatest crosswise area of the slider is: at the:

upperend: 12 of the edges 1 and 8 of the slider.

As before stated in the. usual manufacture or. sliders of this type the cavities for the sides I and 2 in the respective, mould members extend in. substantial parallelism with the contacting surfaces of the mould sections and require the 1186101", floating cores: a v heretofore described. In;

the present construction the greatest areas of the mould cavities, which correspond to the section 12 of the slider above described, register at the contacting surfaces of the mould members and extend therefrom into the respective moulds in axial alinement. Ordinarily, but not necessarily, the contacting surfaces of the mould sections are in horizontal position and the core sections, which consequently extend perpendicularly to such contacting surfaces, are in vertical position, as illustrated herein. In the construction thus described the upper mould section I3 is in fixed position and the lower mould section 14 is movable downwardly relatively thereto.

As illustrated in Figs. 3 and 4 the lower mould cavity i5 is of downwardly tapering rectangular cross section and is provided with a lateral channel l6 for the bridge. The cavity of the upper mould member which registered with the cavity of the lower mould member is provided with a lateral channel i l which registers with the channel 16 in the lower mould section and completes the mould for the bridge. The converging passages for the entrance of the stringers which communicate with the common guideway for the interlocking members on the stringers are formed by complementary interengaging core members which preferably are so constructed that the core member in the lower mould section telescopes into the complementary member in the upper mould section. As illustrated herein the core for the lower mould section has a base portion I8 which is fixedly and preferably detachably secured in a complementary socket in the lower mould member and an upwardly extending core I9 which is provided at its upper end with a downwardly curved recess 23, the portion 19 of the core member being of approximately uniform cross sectional area throughout its length.

The upper end of the core member 2| similarly fits in a socket in the upper mould member in axial alinement with the lower core and is provided with downwardly converging side portions 22 and 23 which telescopically engage the upwardly extending core member IQ of the lower mould section. The outer walls of the portions 22 and 23 are so spaced from the wall of the cavity l5 as to provide converging edge walls having inwardly extending flanges 24 and 25, the edges of which are suitably spaced apart to permit the stringer having interlocking members thereon to be guided through the slider. The upper core member is provided with a recess to form a cavity communicating withthe cavities for the side walls for forming the web member 3 which connects the side walls of the slider as illustrated in Fig.2. 7

Any suitable means may be provided for detachably locking the cores in the respective mould sections. As illustrated herein channels 26 having parallel walls extend transversely into and through the respective mould sections and slightly tapering wedges 21, which are driven into the channels, firmly but detachably anchor the respective core members in place. Obviously any other sort of means may be employed for detachably securing the cores in the respective mould members.

In order to form the bridge 9 a sliding core 28 is mounted in suitable complementary ways 29' and 3B in the upper and lower mould members and crosses the channels E6 and H in said members, as shown in Figs. 1, 5, and 6. The sliding core 28 is provided with an inclinedslot 3i which extends at a suitable angle to the longitudinal axis of the core 28. A bar 32, which slidably fits within the slot 3|, is provided with an end portion 33 which extends through a boss 34 integral with or Welded to the side of the upper mould member. The upper end of the offset extension 33 of the bar 32 is of cylindrical form and is provided with a threaded upper end which is engaged by a nut 35 adapted to clamp the member 32 fixedly in position.

When the mould members are moved to closed position, as illustrated in Fig. 5, the core 28 is forced inwardly across the channel IB-ll, as illustrated in Fig. 3. When the lower or movable mould member is separated from the fixed mould member the core 28 is withdrawn as illustrated in Fig. 6.

Suitable means are provided for charging the cavity of the mould. As illustrated herein the upper member of the mould is provided with a sprue 36 which communicates with a gate 31 which in turn preferably communicates with the channel l6l'l of the bridge. When therefore molten material, such as a thermoplastic or diecasting material, is forced under high pressure into the mould it flows through the sprue, the gate and channel IB-ll into the cavities of the mould completely filling them in such manner as to form the side walls with their flanges and the connection between the side walls. When the mould is thus filled and cooled sufiiciently to congeal the molten material the lower mould member is separated from the upper, thereby withdrawing the core which forms the pull slot and as the mould members separate the complete slider is withdrawn by the sliding core 28 from the mould sections from which it can be readily removed.

It will be understood that the particular embodiment of the invention shown and specifically described herein is of an illustrative character and is not restrictive of the meaning and scope of the following claims.

Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

1. Apparatus for moulding sliders for separable fasteners, of the type having side walls integrally united at one end by an inwardly'converging web with the edges of said side walls diverging from said end to a maximum width approximately midway of the length of the slider to provide converging entrance channels for the toothed stringers of said fastener and having converging flanged edges extending from said maximum width merging into parallel flanged edges providing a single relatively narrow channel to cause interlocking of the teeth of said stringers, and a bridge member, integral at its ends with and spaced therefrom from one of said side walls and extending longitudinally thereof, said moulding apparatus comprising a single stationary mould section and a single relatively movable mould section having complementary flat contacting surfaces with complementary cavities having walls conforming to the side members of said slider extending therefrom into the respective mould sections with their greatest cross sectional area registering at said contacting surfaces and complementary axially alined telescopically engaging core members within the respective cavities each extending into the cavity of the other conforming to the converging channels and to the single channels communicating therewith,

said core members having cooperating cavities uniting the cavities of said side members to produce the web uniting them, and longitudinally extending registering channels inthe wall of one of said side member cavities providing a cavity for producing the bridge of the slider a sprue hole in the upper mould section and a gate leading therefrom to said bridge cavity, registering ways in the contacting faces of said mould sections extending transversely of said bridge cavity, and a metal core slidably mounted in said Ways extending across the bridge cavity for forming the longitudinal pull slot therein.

' 2. Apparatus for moulding sliders for separable fasteners as defined in claim 1, in which the complementary telescopically arranged core members in the cavities of said mold section are of frangible material and means for detachably securing them in said cavities for removal and for replacement when damaged.

3. Apparatus for moulding sliders for separable fasteners as defined in claim 1, in which the core for producing the slot in the bridge member is slidably mounted in communicating ways in the respective mould sections and means operable by initial separation of the mold members to withdraw the slot-producing core from the bridge cavity and thereby to permit removal of the slider from the mold.

4. Moulding apparatus for the slider of slide fasteners having a bridge extending lengthwise of and spaced from one side of the slider and integrally connected at its ends thereto to form a pull slot comprising a single stationary mould section and a single relatively movable mould section having contacting surfaces, the mould sections having complementary cavities conforming to the side walls of the slider, said mould cavities having their greatest crosswise area registering at said contacting surfaces and extending therefrom into the respective mould sections and a longitudinal channel for the bridge, complementary telescopically interengaging cores within the respective cavities conforming to the contour of the guideways through the slider having complementary recesses communicating with said cavities to form the web of the slider, means detachably securing the cores to the respective mould sections in axial alinement, a sliding core mounted in complementary guideways in said mould sections adapted to pass transversely through the bridge channel, means for introducing moulding material into the bridge channel to fill the cavities of the mould from both ends, an arm mounted on the stationary mould section and extending downwardly and outwardly therefrom slidably fitting a complementary similarly inclined recess in the end portion of the sliding core operable upon closing of the mould to insert said sliding core through said channel and upon opening of the mould to withdraw said sliding core from the channel and remove the slider from the stationary mould section.

JOHN BOLTEN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,624,224 Easterlin Apr. 12, 1927 2,209,413 Marinsky July 30, 1940 2,262,053 Schultz Nov. 11, 1941 2,266,887 McCoy Dec. 23, 1941 2,325,687 Kux Aug. 3, 1943 2,362,583 Piperoux Nov. 14, 1944 2,374,292 Kuna Apr. 24, 1945 2,415,395 Ulrich Feb. 4, 1947 

